CFL1, a WW Domain Protein, Regulates Cuticle Development by Modulating the Function of HDG1, a Class IV Homeodomain Transcription Factor, in Rice and Arabidopsis

• Published in: The Plant cell Vol. 23; no. 9; pp. 3392 - 3411
• Main Authors: Wu, Renhong, Li, Shibai, He, Shan, Waßmann, Friedrich, Yu, Caihong, Qin, Genji, Schreiber, Lukas, Qu, Li-Jia, Gu, Hongya
• Format: Journal Article
• Language: English
• Published: England American Society of Plant Biologists 01.09.2011
• Subjects: Abscission; Animal cuticle; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Epidermal cells; Epidermis; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Leaves; Leucine Zippers; Mutagenesis, Insertional; Oryza - genetics; Oryza - growth & development; Oryza - metabolism; Phenotypes; Plant cells; Plant cuticle; Plant Epidermis - growth & development; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - growth & development; Plants, Genetically Modified - metabolism; Rice; Transcription Factors - genetics; Transcription Factors - metabolism; Transgenic plants; Waxes
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.111.088625

Plants have a chemically heterogeneous lipophilic layer, the cuticle, which protects them from biotic and abiotic stresses. The mechanisms that regulate cuticle development are poorly understood. We identified a rice (Oryza sativa) dominant curly leaf mutant, curly flag leafi (cfl1), and cloned CFL1, which encodes a WW domain protein. We overexpressed both rice and Arabidopsis CFL1 in Arabidopsis thaliana; these transgenic plants showed severely impaired cuticle development, similar to that in cfl1 rice. Reduced expression of At CFL1 resulted in reinforcement of cuticle structure. At CFL1 was predominantly expressed in specialized epidermal cells and in regions where dehiscence and abscission occur. Biochemical evidence showed that At CFL1 interacts with HDG1, a class IV homeodomain-leucine zipper transcription factor. Suppression of HDG1 function resulted in similar defective cuticle phenotypes in wild-type Arabidopsis but much alleviated phenotypes in At cfl1-1 mutants. The expression of two cuticle development-associated genes, BDG and FDH, was downregulated in At CFL1 overexpressor and HDG1 suppression plants. HDG1 binds to the cis-element L1 box, which exists in the regulatory regions of BDG and FDH. Our results suggest that rice and Arabidopsis CFL1 negatively regulate cuticle development by affecting the function of HDG1, which regulates the downstream genes BDG and FDH.